1. Field of the Invention
This invention relates to an oil burner nozzle having a nozzle head with a nozzle bore as well as oil supply members, such as a retarding disk and an oil filter, particularly for direct screw connection with an oil preheater of an oil burner.
2. Description of Prior Art
In a home heating system the function of the oil burner nozzle as the muzzle piece is not only to spray the oil under pressure into the combustion chamber, but because of its structural arrangement and the intentional formation of a spraying pattern of the atomized oil it also considerably contributes to good combustion of the heating oil. A poor spraying pattern regularly reduces the efficiency of the entire heating system. For this reason, it has become the custom to check and, if required, readjust the oil spray effect of a burner nozzle in the course of normal maintenance of a heating system.
The area of the nozzle bore, in particular of the very narrow tangential slits in the retarding disk directly ahead of the nozzle bore, is a natural, often occurring trouble area because of the danger of blockage. Nozzle filters are presently used, almost without exception, for avoiding the danger of blockage and are also intended to catch fine dirt particles immediately ahead of the nozzle. Simple screens used in older conventional nozzles, which were intended more for retaining larger pieces of dirt, are useless with respect to fine particles. Filter inserts are almost exclusively used today which can also become blocked, particularly as the porosity of the filter material becomes relatively fine. Increased demands on the total degree of efficiency of combustion, together with continued reduction in the use of oil, make the greatest demands on the function of the oil burner nozzle.
In contrast to a pure water or steam nozzle, the oil burner nozzle is subject to at least one very particular requirement. The interior surface of the oil burner nozzle guides the preheated liquid oil to the outlet nozzle. The exterior of the nozzle extends with its nozzle tip directly into the combustion chamber. Thus, the oil burner nozzle is unavoidably and considerably heated. So that the nozzle can maintain a satisfactory degree of effectiveness together with long service life, in the known oil burner nozzles at least the nozzle head and the retarding disk are constructed of high quality chromium steel and the nozzle oil filter is constructed of a sinter metal.
Without a doubt, the problem of achieving long service life with continuous use of the oil burner nozzle is currently solved with the use of highly heat-resistant materials. However, recent complaints have arisen with respect to retarded drip as a trouble source. It is known that in many uses, the oil burner nozzles continue to drip after the burner flame is extinguished. The large the oil burner nozzle, the more often such retarded drip occurs which, in the extreme case, can lead to the formation of a pool of oil at the bottom of the combustion chamber. It is apparent that such retarded drip problem can result in damage. It has been attempted to avoid at least heavy afterflow by the interposition of special valves, analogously to the problem area of dripping prior to the ignition of the burner flame. Each drop of oil which is not correctly atomized results in degradation of the combustion, in particular in an increase in uncombusted fuel. Thus, retarded dripping always results in an increased output of uncombusted hydrocarbon compounds, which constitute a considerable portion of air pollution.